The present invention is related generally to systems employing at least two computers at remote locations from each other which have provision for the interchange of data between the system computers. More specifically, the present invention is related to those computer-to-computer systems in which an address message precedes the actual data message. This address contains information advising all receiving stations which station will transmit next.
Present communications network receivers use signal amplitude to control the receiver gain. The slow response time causes loss of data when a weak signal follows a strong signal and when a strong signal follows a weak signal. This situation arises, for instance, where one station, e.g. a ship, is nearby and is transmitting a signal that is of sufficient amplitude to saturate the receiver and another station, e.g. another ship, that is at a relatively distant location and is transmitting a signal that is of minimal amplitude at the receiver. The receiver, of course, in this situation must be fast enough to accommodate both the weak and the strong signal. In a Navy computer-to-computer communication system known as Link-14, this problem of accommodating reception of both weak and strong signals has been perfunctorily remedied by including in the actual message format a dead time known as automatic gain control (AGC) settling time. This settling time is illustrated schematically in FIG. 2 which illustrates the present Link-14 data frame format of using five AGC frames followed by three intelligence frames. As is readily apparent from FIG. 2, if a long message is transmitted then the AGC settling time becomes a small percentage of the total message. Most of the time, however, long messages are not sent and only the header, short message is transmitted. In that case the AGC settling time becomes almost half of the message. Obviously then great increases in the data rate can be achieved by eliminating this AGC settling time.